wpa_supplicant: Add initial roaming support

This commit adds different features from 802.11k and 802.11v
specifications to make the device ready for network assisted
roaming. It also adds initial framework for device to detect
whether it needs to move to a better AP.

Followings are added as part of this.

1. Support for sending neighbor report request and provide
   the report back to the APP.
2. Support for beacon measurement report.
3. Support for link measurement report.
4. Support for sending bss transition management query frame
   (triggered by the APP).
5. Support for bss transition management request and move
   to the candidate based on that.
6. Sending the bss transition management response.

components/wpa_supplicant/src/utils/bitfield.c

@@ -0,0 +1,89 @@
+/*
+ * Bitfield
+ * Copyright (c) 2013, Jouni Malinen <j@w1.fi>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "bitfield.h"
+
+
+struct bitfield {
+	u8 *bits;
+	size_t max_bits;
+};
+
+
+struct bitfield * bitfield_alloc(size_t max_bits)
+{
+	struct bitfield *bf;
+
+	bf = os_zalloc(sizeof(*bf) + (max_bits + 7) / 8);
+	if (bf == NULL)
+		return NULL;
+	bf->bits = (u8 *) (bf + 1);
+	bf->max_bits = max_bits;
+	return bf;
+}
+
+
+void bitfield_free(struct bitfield *bf)
+{
+	os_free(bf);
+}
+
+
+void bitfield_set(struct bitfield *bf, size_t bit)
+{
+	if (bit >= bf->max_bits)
+		return;
+	bf->bits[bit / 8] |= BIT(bit % 8);
+}
+
+
+void bitfield_clear(struct bitfield *bf, size_t bit)
+{
+	if (bit >= bf->max_bits)
+		return;
+	bf->bits[bit / 8] &= ~BIT(bit % 8);
+}
+
+
+int bitfield_is_set(struct bitfield *bf, size_t bit)
+{
+	if (bit >= bf->max_bits)
+		return 0;
+	return !!(bf->bits[bit / 8] & BIT(bit % 8));
+}
+
+
+static int first_zero(u8 val)
+{
+	int i;
+	for (i = 0; i < 8; i++) {
+		if (!(val & 0x01))
+			return i;
+		val >>= 1;
+	}
+	return -1;
+}
+
+
+int bitfield_get_first_zero(struct bitfield *bf)
+{
+	size_t i;
+	for (i = 0; i < (bf->max_bits + 7) / 8; i++) {
+		if (bf->bits[i] != 0xff)
+			break;
+	}
+	if (i == (bf->max_bits + 7) / 8)
+		return -1;
+	i = i * 8 + first_zero(bf->bits[i]);
+	if (i >= bf->max_bits)
+		return -1;
+	return i;
+}